Ball valve and method for production thereof

ABSTRACT

The invention provides a ball valve excelling in economy due to the efforts devoted to the reduction of cost, enjoying light weight and high reliability, manifesting high and uniform accuracy, and enabling manufacture of compact finished products having a small interface dimension, and provides a method for the production of the ball valve. The ball valve includes a body formed from a pipe having a predetermined length by subjecting opposite terminal parts (ends) of the pipe to a plastic processing including flaring and diametrical contraction. The body has at a central position a seat-shaping part (seat) formed with a stem-inserting hole, a stem inserted into the stem-inserting hole, a ball disposed non-rotatably at a lower terminal of the stem, and a pair of inserting members having an annular shape forced into the body from opposite terminals of the body. Opposite terminal faces of the body are compression-formed so that the pair of inserting members receive and support the ball rotatably.

This application is a divisional of U.S. application Ser. No.10/182,552, filed Jul. 30, 2002 now U.S. Pat. No. 6,916,011, which is anational stage application of International application No.PCT/JP01/00763, filed Feb. 2, 2001, now allowed.

TECHNICAL FIELD

This invention relates to a ball valve that is fitted in a pipe for coldor hot water, air or gas, and used therein to start, stop or control theflow of the relevant fluid, and to a method for the production thereof.

BACKGROUND ART

Generally, a forged or cast blank or a round bar material is cut to forma main body, and necessary internal parts are incorporated, screwed orbolted in the main body, thereby assembling ball valves of this class.

These ball valves, however, are expensive because they entail highmaterial costs on account of large numbers of man-hours, high prices ofblanks, and large numbers of component parts, and require high processcosts for the cutting and the assemblage. They have comparatively greatweights as well. Further, since the blanks for processed partsnecessitate margins for machining in advance, the costs of materialsinevitably increase proportionately.

To cope with these problems, the concept of forming a ball valve byresorting to the technique of press working utilizing a pipe has beenproposed. (Refer to JP-A SHO 62-165081, JP-A SHO 63-266276 and JP-A HEI10-122390.)

However, since the ball valve produced by the press working techniqueusing a pipe has a construction such that it acquires a sealing propertyby having a ball tightened in a valve seat part, such as a ball seat,which is an elastic member during the assembly of the ball valve, theincorporation of internal components into the pipe necessitates a stepof tentative assemblage using the internal components as an integralunit.

The ball valve, therefore, encounters the problem of adding a step oftentative assemblage and a step of dissolving the tentative assemblage,increasing the total number of steps of operation and boosting the costof production.

Even if the tentative assemblage of internal components should beavoided, manufacturing ball valves uniformly with high accuracy asfinished products by the technique under discussion has proved extremelydifficult.

The screw connection is prevalently adopted generally for connecting avalve with a small diameter to a pipe. When the ball valve utilizing apipe is joined to a pipe by the screw connection, since the constructionof this ball valve requires a screw part different from the valve seatmember to be welded to the terminal part of the body made of the pipe orfastened to the terminal part (expanded diametrically in advance) of thebody made of the pipe, this screw connection incurs the problem ofcomplicating the process of production of the ball valve and undulyelongating the interface dimensions of the valve.

This invention which has been developed in view of the problemsmentioned above is aimed at providing a ball valve excelling in economydue to the efforts devoted to the reduction of costs, enjoying lightweight and high reliability, manifesting high and uniform accuracy, andenabling manufacture of compact finished products having a smallinterface dimension, and is aimed at providing a method for theproduction of the ball valve.

SUMMARY OF THE INVENTION

To attain the above objects, the present invention provides a ball valvecomprising a body formed from a pipe having a predetermined length, bysubjecting opposite terminal parts of the pipe to a plastic processingincluding flaring and diametrical contraction. The body has at a centralposition a seat-producing part formed with a stem-inserting hole, a steminserted into the stem-inserting hole, a ball disposed non-rotatably ata lower terminal part of the stem, and a pair of inserting members withan annular shape forced into the body from opposite terminals of thebody. Opposite terminal faces of the body are compression-formed so thatthe pair of inserting members receive and support the ball rotatably. Inthe ball valve, the plastic processing is angular flaring work so thatthe body has angular opposite terminal faces, and the paired insertingmembers have similar angular outer peripheral faces.

The present invention also provides a method for the production of aball valve, comprising cutting a pipe in a predetermined length,subjecting opposite terminal parts of the length of the pipe to plasticprocessing including flaring and diametrical contraction, therebyforming a body, forming a stem-inserting hole in seat producing partsformed at an approximately central position of the body, then forcingone of a pair of annular inserting members into the body from one sidethereof, joining a ball non-rotatably to a lower terminal of a steminserted into the stem-inserting hole, forcing the other of the pair ofinserting members into the body from the other side thereof, and causingthe pair of inserting members to receive and support the ball rotatably,with a predetermined allowance for tightening furnished for the ball,while compression-forming opposite terminal faces of the body.

The present invention further provides a ball valve having aconstruction comprising a predetermined length of a pipe havingstem-inserting holes at an approximately central position of the pipe,stems inserted in the stem-inserting holes, a ball joined non-rotatablyto lower terminals of the stems, and a pair of annular inserting membersset on inner peripheries of opposite terminals of the pipe. Oppositeterminal faces of the pipe are diametrically contracted or compressed tojoin the pair of inserting members to the pipe and cause the pair ofinserting members to receive and support the ball rotatably.

The present invention further provides a method for the production of aball valve, comprising cutting a pipe in a predetermined length, formingstem-inserting holes in the pipe at an approximately central positionthereof, inserting stems into the stem-inserting holes, setting a ballin a non-rotatable manner to lower terminals of the stems, setting apair of annular inserting members to inner peripheries of oppositeterminals of the pipe and causing the pair of inserting members toreceive the ball from opposite sides of the pipe and rotatably supportthe ball, and diametrically contracting or compressing the oppositeterminals of the pipe until the inserting members and the pipe arejoined.

The present invention further provides a method for the production of aball valve, comprising cutting a pipe in a predetermined length, formingstem inserting holes in the pipe at an approximately central positionthereof, setting an annular inserting member on an inner periphery ofone of opposite terminals of the pipe, and diametrically contracting orcompressing the one terminal of the pipe, thereby fixing the insertingmember. Stems are then inserted into the stem-inserting holes, and aball is non-rotatably joined to lower terminals of the stems.Thereafter, another annular inserting member is set on an innerperiphery of the other terminal of the pipe, thereby causing the pair ofinserting members to receive and support the ball rotatably, and theother terminal of the pipe is diametrically contracted or compressedagainst the other inserting member, thereby joining the other insertingmember and the pipe.

The present invention further provide a ball valve comprising a pipe ofa predetermined length having stem-inserting holes formed therein andterminals diametrically contracted to form seal-retaining parts, a pairof seal rings (one of which is set in one of the seal-retaining parts)stems inserted into the stem-inserting holes, and a ball joinednon-rotatably to a lower terminal of the stems. The ball has one sidethereof colliding with the one seal ring, and the other of the sealrings is allowed to collide against the other side of the ball. Aninsert ring is incorporated on a rear terminal side of the other sealring, and the other seal ring and the insert ring are retained by theother of the seal-retaining parts.

The present invention further provides a method for the production of aball valve, comprising cutting a pipe in a predetermined length,diametrically contracting terminals of the pipe, thereby formingseal-retaining parts of a tapered shape and stem-inserting holes. One ofa pair of seal rings is set on one of the seal-retaining parts, then aball is joined to a stem inserted into one of the stem-inserting holes,thereby allowing one side of the ball to collide against the one sealSubsequently, the other of the pair of seal rings is set on the otherside of the ball, an insert ring is incorporated in the other seal ringon the rear terminal side thereof, and then the other of theseal-retaining parts is caused to set and retain the other seal ring andthe insert ring.

According to this invention, therefore, the attempt to allow the producta decreased weight can be fulfilled because the product using aninexpensive pipe as the blank for its main body has a lighter weightthan the conventional cast or forged product. Since the product of thisinvention requires no cutting step as compared with the conventionalproducts which require cutting steps for the sake of their main bodies,lids and various joined parts, it permits a marked decrease in the timefor production and adapts itself for mass production as well. As aresult, the cost of production can be greatly lowered, and a ball valveveritably excelling in economy can be produced. Further, the ball valveto be obtained by this invention enjoys inexpensiveness and hasincreased reliability because it uses a body of one-piece constructionand has joined portions and component parts in very small numbers.

The ball valve can manifest a sealing force and an operating torquestably because it is formed by expanding the diameter and contractingthe diameter of a given pipe. Since insert members are forced in aspressed at the opposite terminals thereof, and the pressure welding of aball seat to a ball is attained by uniform exertion of pressure, theball valve to be obtained as a finished product enjoys high accuracy.

Further, since various members, such as the insert members and the ball,can be inserted into the body and readied for assemblage withoutrequiring tentative assemblage, the time for assemblage is shortened.Since the insert members are not required to be furnished with portionsfor securing mutual distances, the ball valve to be obtained has adecreased weight, and the insert members incorporated therein can easilyassume various states of needed contact and facilitate adaptation of aproduct.

The ball valve, despite the use of a pipe, does not need to elongate theinterface dimension. Thus, the ball valve is obtained in a compactconstruction composed of only a small number of components.

In the invention described above, the ball valve is configured byperforming a burring work on a stem-inserting hole to form a tubularpart and a stopper piece projecting from part of the tubular part, whileforming a notched groove for regulating rotation in a flange partdisposed on a stem. Thus, the stopper piece to come into working contactwith the notched groove to regulate the rotation of a ball, an O-ringfitted in a fitting groove of the stem can contact the inner wallsurface of the tubular part, and a stepped part can be formed on theupper edge part of the tubular part and packing can be fitted in thestepped part.

Since the consequent impartation of the function of a stopper to theinterior of the body contributes to attainment of compaction of theproduct and reduction of the cost of production and results inintegrating the body with the stopper function, the ball valve producesan open-shut motion with increased accuracy and allows the handle of thevalve to operate with a simple construction. Thus, the ball valve enjoyshigh yield of production and veritably excels in mass-producibility.Further, this invention warrants production of a ball valve that adaptsto widely-varied characteristics (temperature, pressure, etc.) of afluid and exhibits an ideal sealing property.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory diagram illustrating a method for theproduction of a ball valve in the first aspect of this invention.

FIG. 2 is a cross section illustrating the ball valve in the firstaspect of this invention.

FIG. 3 is a plan view of the body shown in FIG. 2.

FIG. 4 is a cross section illustrating another example of the ball valvein the first aspect of this invention.

FIG. 5 is a plan view of FIG. 4.

FIG. 6 is a cross section illustrating an example of providing a bodywith a stepped part.

FIG. 7 is a front view illustrating a stem part.

FIG. 8 is a bottom view of FIG. 7.

FIG. 9 is a cross section illustrating yet another example of the ballvalve in the first aspect of this invention.

FIG. 10 is a plan view of FIG. 9.

FIG. 11 is a cross section of a tube having a predetermined length,illustrating one example of a process for the production of a ball valvein the second aspect of this invention.

FIG. 12 is a cross section illustrating, in a contracted diameter, theneighborhood of the central part of the pipe of FIG. 11.

FIG. 13 is a cross section illustrating the state of the pipe of FIG. 12having internal parts incorporated therein.

FIG. 14 is a cross section illustrating a ball valve in the secondaspect of this invention.

FIG. 15 is a cross section illustrating another example of the ballvalve in the second aspect of this invention.

FIG. 16 is a partially magnified cross section of FIG. 14.

FIG. 17 is a partially magnified cross section of FIG. 15.

FIG. 18 is a plan view of the body of FIG. 14.

FIG. 19 is a cross section of the insert members of FIG. 16.

FIG. 20 is a cross section of a pipe having a predetermined length,illustrating one example of the process for the production of a ballvalve in the third aspect of this invention.

FIG. 21 is a cross section illustrating one side of the pipe of FIG. 20in a diametrically contracted state.

FIG. 22 is a cross section illustrating the pipe of FIG. 21 in a statehaving internal components incorporated therein.

FIG. 23 is a cross section illustrating the pipe of FIG. 22 in a statebeing diametrically contracted with a jig.

FIG. 24 is a magnified cross section of a seal ring in the third aspectof this invention.

FIG. 25 is a magnified cross-section of an insert ring in the thirdaspect of this invention.

FIG. 26 is a magnified cross section illustrating the seal ring in astate having the insert ring incorporated therein.

FIG. 27 is a partially cutaway plan view of the pipe, illustrating therelation between a stem-inserting hole and a thrust washer.

FIG. 28 is a cross section illustrating the ball valve of the thirdaspect of this invention in a state being provided with a rotatable capnut.

FIG. 29 is a cross section illustrating the ball valve of the thirdaspect of this invention in a state being provided with a soldered capnut.

FIG. 30 is a cross section illustrating the pipe provided at theterminal thereof with a cap nut fitted thereto by the work of flaring.

FIG. 31 is a cross section illustrating one example of providing thepipe at the terminal thereof with a joining part.

FIG. 32 is a diagram illustrating another example of the body shown inFIG. 21 in the third aspect of this invention.

FIG. 33 is a partially magnified cross section illustrating anotherexample of the construction for sealing the stem in this invention.

FIG. 34 is a partially cutaway plan view illustrating another workingexample of the handle.

FIG. 35 is a magnified cross section taken through FIG. 34 along lineA-A.

FIG. 36 is a referential plan view depicting the work of forming asemi-finished product of a handle by stamping from a plate material.

DETAILED DESCRIPTION OF THE INVENTION

This invention will be described more specifically below with referenceto the accompanying drawings. For purposes of this description, the term“inner” means closer to the center of the valve with respect to acentral axis of the valve body (i.e., the axis along which flow occurs),while “outer” means farther from the center of the valve.

FIGS. 1 through 10 are intended to illustrate a method for theproduction of a ball valve as contemplated by the first aspect of thisinvention.

In the diagrams, reference numeral 1 denotes a pipe. This pipe 1 is athin-wall (non-thick-wall) type seamless pipe of copper alloy orstainless steel. Otherwise, it may be a seamed pipe 1 produced byshaping a steel plate in the form of a roll and then converting the rollinto a cylinder by joining the opposed edges of the roll as by welding.A body 2 of a ball valve is formed by cutting a predetermined length ofthis pipe 1, namely the length of a prospective valve box of a ballvalve, deburring the opposite ends of the length of the pipe severed bycutting, and then subjecting the opposite parts of the pipe 1 to thework of flaring. The flaring work in this case consists of plasticprocessing an angular (hexagonal, for example) forcing retaining part 3that assumes a radial plane. Further, the central position of the body 2is constricted or beaten to form a flat seat-shaping part 4, and astem-inserting hole 5 is formed in the internal region of theseat-shaping part 4.

With reference to FIG. 2, reference numeral 12 denotes a ball furnishedwith a through hole 12 a. This ball 12 has a stem fitting face 14 formedat the position for setting a stem 15. By joining a non-circularprojecting part 16 formed at the lower terminal of the stem 15 to thestem fitting face 14, the ball 12 and the stem 15 can be joined in anon-rotary state (i.e., those parts do not rotate with respect to eachother). A flange part 17 formed in the lower part of the stem 15prevents the stem 15 from being flung out by the pressure of a fluid.

Reference numeral 22 denotes a handle. This handle 22 is fixed in anon-rotary state to the stem 15 and clamped fast with a nut 25 through aspring washer 24 and a washer 23 disposed respectively in the upper andthe lower part of the handle 22.

Numerals 6, 6 denote an example of a pair of annular insert members.These insert members 6 are symmetrically incorporated bilaterallyrelative to the ball 12. The insert members 6 each retain on the innerperipheral side of the leading terminal part thereof a seat ring 9endowed with a sealing property. Due to a sealing member (O ring) 10made of resin and set on the outer periphery of insert member 6, eachinsert member can perform the function of a gasket against the innerperipheral face of the body 2.

The insert members 6 are each formed either by rolling a thick-wall pipeor a thick-wall plate, then joining the opposed edges of the roll as bywelding, thereby giving rise to a metallic tube, and cutting the tube byrolling or press working or by drawing a thick-wall plate material intothe shape shown in the diagram by the press working. Otherwise, they maybe formed by precision casting, such as the lost-wax process, or bysintering a metallic powder.

Further, the insert members 6 contemplated by this invention possesssuch a thickness as to manifest fully satisfactory strength during thecourse of joining, and also possess fully satisfactory strength towithstand the force exerted during the forced insertion into the pipe 1.That is, the ball valve of this invention is directed toward allocatingfunctions, decreasing weight and compacting construction by adopting aconfiguration which derives the strength necessary for a pressure vesselmainly from the body 2 formed of a thin-wall pipe 1 and the strength towithstand the impact of joining pipes or of effecting the forcedinsertion into the pipe 1 or the strength necessary for maintaining thebearing stress between the ball 12 and the seat ring 9 mainly from theinsert member 6 which is a thick-wall part. The insert members 6, 6 areeach furnished at the terminal end thereof on the opposite side relativeto the ball 12 with a tapered part 7 disposed at a suitable angle alongthe respective angularly shaped outer peripheral faces 8, 8. Theseinsert members 6 may be endowed with a suitable form of union, such as afemale thread 6 a that is used in the present case. Thus, the body 2 mayhave suitably incorporated therein a portion for union, such as a femalethread, without requiring an alteration in the length of the body 2which Is formed of a predetermined length of the pipe 1.

FIG. 3 is intended to illustrate an example of providing the body in theinterior thereof with a stopper mechanism for a handle. With referenceto this diagram, burring work is performed on the stem-inserting hole 5to form a tubular part 11 of a small length and a stopper piece 13integrally projecting from part of this tubular part 11. Meanwhile, anotched groove 19 for regulating rotation is formed in the flange part17 provided for the stem 15 as illustrated in FIG. 8, and the ball 12 isdisposed so as to have the rotation thereof regulated to an angle ofabout 90 degrees by a stopper mechanism formed by meshing (engaging) thestopper piece 13 and the notched groove 19. Then, by allowing an O-ring18 inserted in a fitting groove 15 a of the stem 15 to contact the innerperipheral face of the tubular part 11 as illustrated in FIG. 2, theball valve can be infallibly sealed with a compact structure. Further,by forming a stepped part 20 on the upper edge part of the tubular part11 and fitting a washer 23, a gland 43 and gland packing 42 at thestepped part 20 as illustrated in FIG. 6, the stem 15 can retain thesealing property and increase the torque performance. In this case, theoperating torque of the handle may be relied on to disperse the forceexerted on the stopper mechanism and prevent the stopper mechanism frombeing deformed by providing the flange part 17 with two notched grooves19 indicated with a chain line, and meshing (engaging) these notchedgrooves 19 and the two stopper pieces 13 as illustrated in FIG. 8.

Now, one example of the method for producing the ball valve in thisinvention will be described specifically below with reference to thedrawings.

With reference to FIG. 1, the body 2 furnished with the forcingretaining part 3 of an approximately hexagonal shape is formed bycutting the pipe 1 in a predetermined length and subjecting the oppositeparts of the pipe 1 to plastic processing resorting to the work offlaring.

The process of seat shaping and perforation is carried out by drawingthe approximately central position of the body 2, thereby forming theseat-shaping part 4 and perforating the seat-shaping part 4, therebyforming the stem-inserting hole 5. Subsequently, burring work isperformed on the stem-inserting hole 5 Due to this burring work, thetubular part 11 and the stopper piece 13 produced by projecting part ofthe tubular part 11 are formed.

Then, one of the pair of annular inserting members 6 similar in shape tothe forcing retaining part 3 is forced into the body 2 through one sidethereof, and thereafter the ball 12 is non-rotatably joined to the lowerterminal end of the stem 15 inserted in the stem-inserting hole 5 asillustrated in the same diagram. In this case, the notched groove 19 forregulating rotation to an approximate angle of 90 degrees is formed inthe flange part 17 provided for the stem 15, and the stopper piece 13 ismeshed (engaging) with the notched groove 19 and incorporated in such amanner in the body as to regulate the rotation of the ball 12. Further,the other inserting member 6 is forced in through the forcing retainingpart 3 on the other side of the body 2. Thereafter, the ball valve isproduced by causing the seat rings 9 of the pair of inserting members 6,6 to support the ball 12 rotatably with a predetermined tighteningmargin allowed for the ball 12 and, meanwhile, simultaneously beatingthe terminal face parts (diametrically contracted parts) 26 on bothsides of the body 2 with jigs 47, thereby compression-forming theterminal face parts along the contour of the tapered part 7 of theinserting member 6. Thus, the ball 12 is supported on the seat rings 9so as to retain the sealing property and the property of torque aspredetermined.

The ball valve using the body 2 of such a straight type as illustratedin FIG. 2 and FIG. 4 is produced through the process described above. Inthe process involving a flaring step as illustrated in FIG. 9, the body2 is formed in the shape illustrated in FIG. 9 by first circularlyflaring the opposite side parts of the pipe 1 and then flaring them in ahexagonal shape. The rest of this process is identical with thepreceding process.

In the embodiment of the ball valve of this invention, since theconstruction of the ball valve varies with the bore size (ball portdiameter), it is proper to apply the construction illustrated in FIG. 2to the ball valve of a full port type and the construction illustratedin FIG. 4 to the ball valve of a reduced port type.

FIGS. 11 through 19 depict a method for producing a ball valvecontemplated in the second aspect of this invention.

Like parts used in the ball valve and the method for production thereofin the present aspect of this invention and in the preceding aspect ofthe invention will be denoted by like reference numerals and will beomitted from the following description.

In FIG. 12, is a seal retaining part 3 a is formed in a tapered shape inthe pipe 2 at an approximately central position thereof by plasticprocessing such as swaging or press working. The seat-producing parts 4are formed in a planar shape as by drawing one each on the outside andinside of the pipe 1 at a position close to the seal-retaining parts 3a, and the stem-inserting hole 5 is formed as well in the area insidethe seat-producing part 4.

Now, the ball valve and the method for production thereof contemplatedby the second aspect of this invention will be described below.

First, the pipe 1 is cut to obtain a length thereof needed to form thebody 2 of ball valve as illustrated in FIG. 11. Then, the pipe 1 isdiametrically contracted in the neighborhood of the central part thereofas illustrated in FIG. 12 to form the seal-retaining parts 3 a, 3 ahaving a tapered shape. The seat-producing parts 4 having a planar shapeare formed in the central part of the pipe 1 at positions close to theseal-retaining parts 3 a, 3 a, and the stem-inserting hole 5 in acircular shape is formed by punching in the area inside theseat-producing part 4.

Then, the stem 15 is inserted into the stem-inserting hole 5 from theinner side of the body 2 and, at the same time, the ball 12 is insertedinto the pipe 1 from either of the sides thereof, with thestem-inserting face 14 held in the direction parallel to the flow pathso as to retain the projecting part 16 of the stem 15 as joined in anon-rotary state to the stem-inserting face 14.

The seat rings 9, 9 and the sealing members (O-rings) 10, 10 arerespectively fitted in the insert members 6, 6 as illustrated in FIG.14. The insert members 6, 6 are inserted into the pipe 1 from theopposite terminal ends thereof until the seat rings 9 which are theleading terminal parts of the inserting members 6 receive and supportthe ball 12 rotatably from opposite sides The sealing members 10 areincorporated in such a state as to contact the seal-retaining parts 3 aclosely to complete a seal.

Subsequently, outer seal-retaining parts 3 b, 3 b are formed in atapered shape by diametrically contracting or compressing the pipe 1 byswaging or press working so as to substantially align the through hole 9a of the seat ring 9 with the through hole 12 a of the ball 12 and sothat the inserting members 6, 6 and the pipe 1 are joined.

Since the seal-retaining parts 3 b are formed closely along the contourof the tapered parts 7 of the inserting members 6, they exert a wedgingeffect on the inserting members 6, 6 and move the inserting members 6, 6slightly toward the ball 12, with the result that the pair of seat rings9, 9 are accurately positioned because their mutual distance is adjustedto the predetermined magnitude. When the sealing members 10, 10 are madeto depress the inner seal-retaining parts 3 a, 3 a, the insertingmembers 6 are aligned more accurately because the wedging effect of thetapered shape of the inner seal-retaining members 3 a, 3 a exerts aforce in the axial direction on the inserting members 6.

It would be advantageous to perform the work of diametrical contractionor compression on the entire periphery of the outer seal-retaining parts3 b along the contour of the tapered parts 7 thereof. So long as eachouter seal-retaining part 3 b is disposed at least at one place alongthe contour of the tapered parts 7, the sealing property between theinserting members 6 and the body 2 can be retained because the sealingmembers 10, 10 are moved toward the ball 12 and brought into contactwith the inner seal-retaining parts 3 a, 3 a. The process describedabove is preferably automated with proper means, such as jigs. Further,the tapered parts 7 of the body 2, while the valve is in use, fulfillthe function of preventing the inserting members 6 from being extractedout of the valve by the inner pressure.

The diametrical contraction can be effected by drawing up to a pluralityof repetitions until the diameter is contracted to the predeterminedmagnitude. Since the division of the work into the plurality of partsmanifests a function of increasing the strength of the part subjected tothe diametrical contraction, it is effective in increasing the strengthof the ball valve and enabling the inserting members 6, 6 to bepositioned more accurately. The quantity of the diametrical contractionand the number of forming processes involved in this case may beproperly decided liberally to suit the relevant operation to beperformed.

FIG. 15 is a cross section illustrating another example of a method forproduction of the ball valve contemplated by the second aspect of theinvention. Like parts used in the present aspect of this invention andin the preceding aspect of the invention will be denoted by likereference numerals and will be omitted from the following description.

In the present example, the production is effected by a procedure whichcomprises preparing the pipe 1 by cutting the pipe to a predeterminedlength, forming the stem-inserting hole 5 in the approximately centralposition of the pipe 1, fitting an inserting member 6 having an annularshape in the inner periphery on one side of the pipe 1, diametricallycontracting or compressing the pipe 1 until the inserting member isfixed to the pipe 1, and then inserting the stem 15 into thestem-inserting hole 5 and joining the ball 12 in a non-rotary state tothe lower terminal of the stem 15 as well.

The procedure further comprises fitting a second inserting member 6 ofan annular shape to the inner periphery on the other side of the pipe 1,causing the pair of inserting members 6, 6 to receive and rotatablysupport the ball 12, and further diametrically contracting orcompressing the pipe 1 toward the inserting member 6 inserted into theinterior of the pipe 1 on the other side until the inserting members 6and the pipe 1 are joined. During the course of the diametricalcontraction or compression, the diametrically contracted parts 26 formedby diametrically contracting the pipe 1 are meshed with depressed parts26 a disposed at proper positions along the outer periphery of theinserting members 6, 6 to fix the inserting members 6, 6 to the pipe 1to prevent them from rotating.

The depressed parts 26 a are each in the form of a notched depressionhaving a slope 26 b of a proper angle on the tube-connecting part(outer) side of the inserting member 6, and a substantially verticalwall on the ball 12 side as illustrated in FIG. 17.

By diametrically contracting or compressing the neighborhood of eitherof the terminal parts of the pipe 1 and then similarly diametricallycontracting or compressing the neighborhood of the other terminal part,it is possible to move the inserting members 6, 6 by the wedging effecttoward the ball 12 and bring the seat rings 9 as aligned axially intotight contact with the ball 12.

In the embodiment of the ball valve of this invention, the ball valve isvaried in construction with the bore size (ball port diameter) thereof.It is advantageous to adopt the construction illustrated in FIG. 15 forthe ball valve of a full port type as in the present example, and adoptthe construction illustrated in FIG. 14 for the ball valve of a reducedport type.

In either of the first and second aspects of this invention, byproviding the inserting members 6, 6 to be inserted each at the oppositeterminal portions thereof with mutually parallel external flat parts 6 bformed in an approximately hexagonal shape as illustrated in FIG. 19, orwith mutually parallel external flat portions formed at places of aneven number of not less than two prior to the diametrical contraction orcompression of the outer periphery of the body 2, it is made possible toform mutually parallel handle parts 2 a in the neighborhood of theopposite terminals of the body 2 as illustrated in FIG. 3 and FIG. 18and enable the handle parts 2 a to be fixed with a fixing jig, such as awrench, and utilized for performing the tube fitting.

FIGS. 20 through 32 depict the ball valves and the methods forproduction thereof as contemplated by a third aspect of this invention.

In FIG. 21, a seal-retaining part 3 a having a tapered shape is formedby diametrically contracting one of the opposite terminal parts (ends)of the pipe 2 by plastic processing, such as swaging or press working.The seat-shaping parts 4 having a planar shape are formed one each onthe inside and the outside of the pipe 1 as by drawing at the close tothe seal-retaining parts 3 a and stopping the diametrical contraction,and the stem-inserting hole 5 is formed in the area inside theseat-producing parts 4.

In FIG. 24, an annular seal ring made of resin is intended to fulfillsimultaneously the functions of a seat ring and a gasket of the body 2.The ball valve uses a pair of such seal rings 27 and they manifest thefunction of a gasket for closely sealing the angular parts on the innerperiphery side with a sealing part 27 a of the ball face and an outerperiphery side 27 b with the inner peripheral surface of theseal-retaining part 3 a of the body 2.

In FIG. 25, reference numeral 28 denotes an insert ring formed of metalin an annular shape. This insert ring 28 has formed on the outerperipheral surface thereof a tapered part 28 a and a straight part 28 b.This tapered part 28 a, due to the wedge effect generated during thediametrical contraction of the pipe 1, increases the accuracy ofpositioning of the seal ring 27 relative to the ball 12.

Then, the straight part 28 b is endowed with the function of preventingthe pipe 1 and the seal ring 27 from being deformed under the load ofdrawing during the diametrical contraction of the pipe 1. In this case,when the tapered part 28 a of the insert ring 28 is fitted into afitting part 27 c formed in a conical cross section on the rear terminalface of the seal ring 27. At the same time, the insert ring 28 isaligned by fitting a projecting part 28 c of the insert ring 28 to astepped part 27 d of the seal ring 27 as illustrated in FIG. 26, theseal ring 27 follows such motions until the seal ring 27 is incorporatedin a concentric state in the ball valve.

A thrust washer 18 a is interposed between the flange part 17 and theseat-shaping part 4 both formed at the lower part of the stem 15. Thediameter of this thrust washer 18 a is set at the magnitude D that hasan allowance in advance for the elliptic strain due to the diametricalcontraction of the pipe 1 (d+Δd) (D>d+Δd) as illustrated in FIG. 27.This diameter is large enough to avoid hindering the smooth motion ofthe stem.

With reference to FIG. 23, a first jig 29 a is made to support the sideof the seal-retaining part 3 a formed at one of the terminal parts ofthe pipe 1, a second jig 29 b is made to support the seal ring 27, andforming jigs 30 a, 30 b are disposed on the other terminal part side(end) of the pipe 1. With the first forming jig 30 a pressing in thedirection of the arrow, the pipe 1 is diametrically contracted byplastic processing, such as swaging or press working, and aseal-retaining part 3 c is formed in a tapered shape. In this case, bypressing the forming jig 30 a across a distance L, it is made possibleto adjust the mutual distance of (distance between) the pair of sealrings 27, 27 to a predetermined magnitude and position the seal ringsaccurately.

With reference to FIG. 28 and FIG. 29, reference numeral 22 denotes thehandle. This handle 22 is attached in a non-rotary state to the stem 15and is provided with a stopper adapted to stop the handle rotation atangular intervals of about 90 degrees, and is fixed by tightening withthe nut 25 through the spring washer 24 and a washer 23 which aredisposed respectively on and beneath the handle 22.

As another example, the provision of a stopper mechanism similar to thepreceding aspects of the invention is conceivable. To be specific, thestem-inserting hole 5 is subjected to burring work to form the tubularpart 11 having a short length and a stopper piece 13 projectingintegrally from part of the tubular part 11 as illustrated in FIG. 32.Meanwhile, the notched groove 19 for regulating rotation is formed inthe flange part 17 and, due to the stopper mechanism obtained by meshingthe stopper piece 13 with the notched groove 19, the ball 12 is disposedso as to have the rotation thereof regulated at an angle of about 90degrees. Further, by setting the washer 23, a gland 43 and gland packing42 in the upper edge part of the tubular part 11 as illustrated in FIG.6, the stem 15 can retain the sealing property and enjoy an improvementin the property of torque.

FIGS. 28 through 31 depict varying examples of the joining parts whichare formed at the opposite terminal parts of the ball valve contemplatedby the third aspect of this invention.

FIG. 28 illustrates a construction produced by forming flared parts 31one each at the opposite terminal parts (ends) of the pipe 1, causingthe leading (inner) terminal projecting parts 32 a of cap nuts 32, 32 toabut the flared parts 31, and slanting the leading terminal projectingparts 32 a of the cap nuts 32, 32 as by roller pressing until theseparts closely contact the flared parts 31.

FIG. 29 illustrates a construction produced by inserting the cap nuts 33into the opposite terminal parts (ends) of the pipe 1 and joining themby welding 33 a, such as soldering. FIG. 30 illustrates an example ofthe construction produced by having the cap nuts 34 incorporated inadvance in the opposite terminals of the pipe 1, then flaring theopposite terminal parts of the pipe 1 to form diametrically expandedparts 35, and allowing the cap nuts 34 to be disposed rotatably at thepositions of union as illustrated in the diagram.

FIG. 31 illustrates a construction produced by flaring the oppositeterminal parts of the pipe 1 at an approximately right angle to formengaging parts 36, and joining fitting parts 37 a of adjoining members37 and the engaging parts 36 with special clamps 38.

Now, one example of the method for production of the ball valvecontemplated by the third aspect of this invention will be described.

For a start, the pipe 1 is cut in a length for forming the body 2 of theball valve as illustrated in FIG. 20. Then, the seal-retaining part 3 ais formed in a tapered shape by diametrically contracting one of theterminal parts (ends) of the pipe 1, the seat-shaping part (i.e., seat)4 having a planar shape is formed in the central part of the pipe 1 at aposition close to the seal-retaining part 3 a, and the stem-insertinghole 5 is formed in a circular shape by performing a punching work inthe area inside the seat-producing part 4 as illustrated in FIG. 21.

Thereafter, the seal rings 27 are inserted into the pipe 1 and set atthe positions of the seal retaining parts 3 a. In this case, the sealrings 27 manifest the function of a gasket to the body 2 by having theouter (external) peripheral surface 27 b thereof tightly seal the inner(internal) peripheral surfaces of the seal-retaining parts 3 a.

The stems are inserted into the stem-inserting hole 5 from the inside ofthe body 2 with the thrust washers 18 a retained on the flange parts 17of the stems 15 and, at the same time, the ball 12 is inserted in thedirection making the stem-fitting surfaces 14 thereof parallel with theflow path into the pipe 1 from the side thereof not yet diametricallycontracted until the projecting parts 16 of the stems 15 are connectedin a non-rotary state to the stem-fitting surfaces 14. Then, the ball 12will collide against the seal rings 27 in a slightly resilient state. Inthis case, the seal rings 6 simultaneously fulfill the functions of aseat ring and a gasket and contribute to the reduction of the number ofcomponent parts of the ball valve.

Then, the other of the pair of seal rings 27 is inserted into the pipe 1from the side thereof not yet diametrically contracted (second side)and, at the same time, the insert ring 28 is inserted into the pipe 1until the tapered parts 28 a of the insert rings 28 are meshed with thefitting parts 27 c of the seal rings 27 as illustrated in FIG. 23. Thevarious steps of the process described above are preferably properlyautomated to suit the particular construction.

Thereafter, the forming jigs 30 a and 30 b are set on the other terminalpart side of the pipe 1, with the jig 29 a supporting the seal-retainingpart 3 a formed in the first opposite terminal part of the pipe 1 andthe jig 29 b supporting the seal ring 27 as illustrated in FIG. 23. Theforming jig 30 b fulfills the function of supporting the rear (outer)end of the insert ring 28 and, at the same time, inserting the jigleading end into through hole 28 d of the insert ring 28, through holes27 e of the seal ring 27, and through holes 12 a of the ball 12 so as toalign and support the relevant members.

Then, with the forming jig 30 a pressing in the direction of the arrow,the pipe 1 is subjected to plastic processing, such as swaging or pressworking, to be diametrically contracted and, at the same time, theseal-retaining part 3 c of a tapered shape is formed. In this case, bypressing the forming jig 30 a across a distance L, it is possible tomove the insert ring 3 a and the seal ring 27 slightly toward the ball12 due to the wedging effect generated during the formation of theseal-retaining parts 3 c having a tapered shape, and to adjust themutual distance of (distance between) the pair of seal rings 27, 27 to apredetermined magnitude and position the seal rings accurately.

The diametrical contraction involved at varying steps mentioned abovemay be effected by drawing up to a plurality of repetitions until thediameter is contracted to the predetermined magnitude. Since thedivision of the work into the plurality of parts manifests a function ofincreasing the strength of the part subjected to the diametricalcontraction, it is effective in increasing the strength of the ballvalve and enabling the parts of the seal rings 27 and the insert rings28 to be positioned more accurately. The quantity of the diametricalcontraction and the number of forming processes involved in this casemay be properly decided liberally to suit the relevant operation to beperformed.

FIG. 32 depicts another example of the body 2 shown in FIG. 21. Itrepresents the case of burring the stem-inserting hole 5 illustrated inthe first and the second aspect of this invention to form a stoppermechanism for the stem (handle) inside the body. The other componentparts of the present construction are similar to those of the precedingexample.

One example of the ball valve contemplated by yet another aspect of thisinvention will be described below. The present example can be applied toother aspects than the first through third aspects of the invention.Like parts will be denoted by like reference numerals and omitted fromthe following description.

In FIG. 33, reference numeral 1 denotes a pipe. This pipe 1 is a pipe ofa thin-wall type made of copper alloy or stainless steel. Alternatively,the pipe 1 may be produced by shaping a steel plate in the form of aroll and then joining the opposed ends of the roll by such means aswelding, thereby imparting a cylindrical form thereto. This pipe 1 iscut in a predetermined length, namely the length for forming a valve boxof a prospective ball valve, the opposite terminals of the length of thepipe 1 are burred, and subsequently plastic processing is performed onthe opposite terminal parts of the pipe 1 to form the body 2 of the ballvalve. A retaining vessel 39 furnished with an angular through hole 39 afor non-rotatably receiving the stem 15 and a retaining ring 40 areformed of a thin plate material by plastic processing, casting, hotforging or injection molding. Then, the flange part 17 of the stem 15 tobe inserted into the stem-inserting hole 5 of the body 2 is placed inthe retaining receptacle 39, a thrust washer 41 is formed in theretaining vessel 39 on the upper side of the flange part 17, and thisthrust washer 41 is interposed between the rear side of the seat-shapingpart (seat) 4 of the body 2 and the flange part 17 as illustrated in thediagram. Meanwhile, the gland packing 42 inserted into the retainingring 40 is positioned on the upper side of the seat-shaping part 4 andset in the stem 15, and the nut 25 is helically fitted to the stem 15and then fixed by tightening through the gland 43 and the washer 23.

The construction thus obtained provides such advantages as preventingthe thrust washer 41 and the gland packing 42 from being deformed orfractured while in service, increasing the sealing effects thereof, andenabling them to withstand protracted use without being affected by thecharacteristic properties (temperature and pressure) of a fluid.

FIG. 34 depicts another example of the handle that can be applied to thevarious aspects of this invention even when the body is not providedtherein with a stopper mechanism for the handle. This handle is producedby deriving an intermediate portion 45 a for a handle 45 from a platematerial 44 by punching and forming a stopper projecting piece 46 in theintermediate portion 45 a by plastic processing.

This handle enjoys a great practical value because it yields no wastematerial, manifests an effect of allowing mass production andcontributes to the reduction of cost.

INDUSTRIAL APPLICABILITY

The ball valve and the method for production thereof contemplated bythis invention as described above are suitable for such a ball valve asis set in piping for cold or hot water, air or gas, and is operated toopen or shut or control the flow of the fluid. Since the ball valve ofthis invention weighs less than the conventional counterparts made bycasting, it realizes a reduction in weight of the product and permits agreat cut in the time spent for the production and allows quantityproduction of ball valves. As a result, the method of production of thisinvention permits a great decrease in the cost of production and allowsprovision of ball valves highly excelling in economy. Though thisinvention is directed toward the ball valve and the method forproduction thereof, it may be suitably applied to the formation ofbodies for valves, such as butterfly valves.

1. A ball valve comprising: a body formed of a predetermined length ofpipe having opposite diametrically-contracted and flared end portions,said body having: a centrally-located flat seat portion; astem-inserting hole formed in said seat portion; a tublar part formed asan integral one-piece construction with said body and extending inwardlyinto an interior of said body from said stem-inserting hole; and astopper piece projecting from said tubular part inside said body; a steminserted in said stem-inserting portion, said stem having a flange witha notched groove arranged to engage said stopper piece so as to regulaterotation of said stem; a ball connected to a lower end of said stem soas to rotate with rotation of said stem; and a pair of annular insertmembers inserted into said body at respective opposite end portions ofsaid body, each of said insert members having an outer pipe-connectingportion with a female thread formed therein, and each of said insertmemebers having a wall thinkness larger than a wall thickness of saidbody; wherein a face of each of said opposite end portions of said bodyis compressed so that said insert members rotatably support said ball.2. The ball valve of claim 1, wherein said flared opposite end portionsof said body comprise angularly-flared end portions, each of said insertmembers having a corresponding angled outer peripheral edge.
 3. The ballvalve of claim 1, wherein said tubular part has an upper edge with astepped part, further comprising packing set against said stepped part.4. The ball valve of claim 1, wherein said stem has a fitting groove,further comprising an O-ring arranged in said fitting groove, saidfitting groove and said O-ring being arranged so that said O-ringcontacts an internal peripheral surface of said tubular part.
 5. Theball valve of claim 4, wherein said tubular part has an upper edge witha stepped part, further comprising packing set against said steppedpart.
 6. The ball valve of claim 1, wherein each of said insert membershas an integral outer pipe-connecting portion so as to have a one-piececonstruction.
 7. A method of producing a ball valve, comprising: cuttinga pipe to a predetermined length; forming a centrally-located flat seatportion in the cut length of pipe to form a body; forming astem-inserting hole in the flat seat portion of the body; performing aburring process on the stem-inserting hole so as to form a tubular partas an integral one-piece construction with the body and extendinginwardly into an interior of the body from the stem-inserting hole, andso as to form a stopper piece projecting from the tubular part insidethe body; inserting under pressure a first one of a pair of insertmembers into the body through a first end of the body, each of the pairof insert members having an outer pipe-connecting portion with a femalethread formed therein, and each of the insert members having a wallthickness larger than a wall thickness of the body; inserting a stemhaving a flange with a notched groove therein through the stem-insertinghole so that the notched groove engages the stopper piece; joining aball to a lower end of the stem inserted through the stem-inserting holeso that the ball is rotatable with rotation of the stem; inserting underpressure a second one of the pair of insert members into the bodythrough a second end of the body; and plastically deforming opposite endportions of the cut length of pipe by flaring and diametricalcontraction, and so that the pair of insert members rotatably supportthe ball with a predetermined tightening allowance.
 8. The method ofclaim 7, further comprising: forming an outer internally-angled sealretaining part at each end of the body; and diametrically-compressing acentral portion of the body so as to form a pair of innerinternally-angled seal retaining parts such that each of the pair ofinsert members is arranged between one of the outer internally-angledseal retaining parts and a corresponding one of the innerinternally-angled seal retaining parts.
 9. The method of claim 7,wherein each of the pair of insert members is formed so as to have anintegral outer pipe-connecting portion so as to have a one-piececonstruction.